Reservoir Characterization and 3-D Modeling Using Combined Techniques from Well Logs to Reservoir Simulation: Case Study in the Serie Inferieure, Hassi R’Mel Field, Southern Algeria

Zohra Nennouche*, Youcef Azoug, and Karim Belabed
Sonatrach, Algeria
*[email protected]

Reservoir characterisation is a key aspect in building a robust reservoir model for reliable simulations, especially in our case where the reservoir is not yet producing. This presentation describes a method used to build a geological model that was converted into a reservoir model for the Tagi Series of Hassi R’Mel South field (HRS), located onshore in north-central Algeria. The study used Petrel^TM software combined with new techniques to preserve the complex variations of the reservoir. Optimising field development required a level of reservoir description that adequately defined vertical and lateral variations in reservoir quality. The method consisted of integrating seismic, petrophysical and geological interpretation. The HRS reservoir formation, known as the Serie Inferieure (SI), has medium to low reservoir quality. The structural model showed great complexity. The results of drilling of three wells, gave 8 m of oil with an average permeability of 50 mD. This encouraged us to develop this reservoir by drilling additional wells before starting production. The SI reservoir represents a challenge for optimising the field development because the heavy oil is located in a highly heterogeneous fluvial reservoir with poor petrophysical conditions. The most important obstacle is that some of the well logs are difficult to interpret due to the naturally radioactive host rocks. The high gamma-ray logs have a high-amplitude response, which masks the reservoir. Another difficulty is that water saturations appear to be very high when interpreted from well logs. To address these problems a multi-disciplinary team used both geological and engineering techniques to develop 3-D numerical models for the effective porosity, permeability, water saturation and facies distribution. These models will be used to calculate the hydrocarbons-in-place and to plan future wells.

AAPG Search and Discovery Article #90077©2008 GEO 2008 Middle East Conference and Exhibition, Manama, Bahrain